Orthodontic anterior traction appliances have been developed which are worn on the head or face of the patient for applying force to selected teeth and/or jaw component(s) to move/modify and position the same. In designing such appliances, important factors to consider are patient comfort including allowing the patient to see clearly and talk while the appliance is worn, adjustability to fit all patients properly, stability of the appliance on the patient's head, and a high degree of versatility in application of force to the patient's teeth and supporting structures.
Typical anterior traction appliances such as a face crib include a frame adapted to be worn on the head of the patient, a forehead rest carried by the frame and adapted to contact the patient's forehead, a chin rest carried by the frame and adapted to contact the patient's chin, and a mouth bow extending forwardly of the patient's mouth when the appliance is in a position of use adapted to be operatively connected by elastic (rubber) bands to selected teeth of the patient. The forehead pad and chin pad function in a manner supporting and positioning the appliance against the patient's face and preventing slippage or undesired movement of the appliance thereby enhancing stability in a manner which is comfortable to the patient.
However, the chin cup is anchored against the patient's chin when providing support and adjustment for the frame. Consequently, lower jaw movement such as that which occurs when talking can cause the movement of the appliance. This, in turn, could interfere with the teeth adjusting process and thereby have a detrimental effect. Further, when the chin cup is in a position of use against the patient's face pressure is exerted against the lower jaw, transmitted unfavorably against the mandibular joint as it relates to the temporal bone and associated disc (meniscus) between (TMJ) which is shown to have a detrimental effect. Therefore, a face crib which is stationary against the patient's face during lower jaw movement and anchored in such a manner that pressure in not exerted against the lower jaw would be desirable.